There is a key rule of thumb (or heuristic) in science known as the Copernican Principle. It essentially says: “We’re not special.” (The “we” in question being the human race.) It’s named after Nicolaus Copernicus, who, in 1543, forever banished the Earth and its thin film of humanity from the center of the universe.
Ever since, the science view of humanity is that it’s just part of the landscape, nothing particularly special, a mere consequence of energy+time creating increasing organization in systems. We may be complex, perhaps even a little surprisingly so, but we’re still nothing special.
Yet it seems to me that, at least in some ways, we really are.
To claim that we’re special (or not) demands a definition of what’s meant by special. The word itself as generally used has four possible meanings: unique, unusual, excellent, or beloved. (Can I touch all four bases? “You have special skills that make you special among your peers, and that’s why you’re specially special to me.” Gotta gimme three outta four on that at least.)
In the Copernican case special means unique or unusual. Humanity is not unique or unusual. (Many may think those two are the same thing, but I had an English teacher who was very particular that unique means there can be only one.) Our existence, my writing this post, you reading it, could happen anywhere in the cosmos.
That much is true. We believe the laws of physics are the same everywhere, so certainly the physical causes that led to us being here could have happened anywhere. In the purest sense of the Copernican principle, we’re not the center of anything.
But I think we might at least be unusual. We might even somewhat unique. (I disagreed with that English teacher.) In addition, it’s possible we’re a little excellent, too.
Two related popular notions express the Copernican principle: the Drake Equation and the Fermi Paradox.
The former is an equation that attempts to quantify the probability of intelligent life. It contains a number of factors that combine to provide a number:
The result, N, depends on those factors, each of which is a wild guess — some wilder than others. (I’m a bit askance at the units in the equation: fractions, a rate, an average, and a timespan. Yikes.)
Astronomers, SETI researchers, and science fiction fans, have long hoped the factors allow our galaxy, the Milky Way, to be teeming with alien life. (Or at least a few, eh?) Even a single species with the right technology, if motivated to explore, could colonize the entire galaxy in under a million years.
The Fermi Paradox, in response to optimistic factor weighting that suggests a busy galaxy, asks plaintively and piteously, “Okay then, so where are they?”
One answer is that a reasonably low estimate of those factors turns up a troublingly low result. The first and last terms are numbers, respectively the rate of star production and the lifetime where a species communicates into space. (Note that the equation is tuned to produce the number of species we might hear from.)
Ignoring those numbers, the middle five terms are factors, some of them much larger than others but let’s average them out and assign odds of 1/10000 to each. That gives us:
Awfully small odds with only 2.5×1011 stars in the galaxy. Those odds make us likely the only intelligent life in the Local Group! SETI is probably wasting its time.
The unknown values of the terms in Drake’s equation, along with the weirdness of the term’s units, inspired me to a simple version based on a set of specific events that seem necessary for intelligent life. I’ve explored all this before. (See Simple Probabilities.) Here I’ll just show you the equation:
Which is pretty much the same thing as above, but here I’m estimating the odds of a single intelligent civilization arising. (And I threw in one more term, so six things with 1/1000 odds necessary for us to be here pondering this.)
Again, the point is that reasonable individual odds result in extraordinary odds overall. We seem to be, at the least, statistically special.
(I would argue that sitting here pondering these things makes us special, too, and maybe a bit excellent.)
One last consideration: We might be the first. We might be The Ancestors future species millions of years from now will be talking about in hushed voices. (Or derisive ones.)
If we grant the universe a lifetime of (at least) one-trillion years, and call that a 24-hour day, then right now, at 13.8 billion years, we haven’t quite reached 00:20 of the day. Not even twenty minutes past midnight.
Our appearance at this time might be unusual. The Earth may only be 4.5 billion years old, which says intelligent life can arise in that time, but it may take many versions of Earth over the cosmic lifetime to produce one that pulls it off.
We may be unique in time, having showed up to the party very early!
Recently I thought of another sense in which we’re a bit unique. It has to do with this chart (you may have seen a similar one somewhere):
It suddenly struck me that, being of only 4.9% of the total energy of the universe is also a bit unique. Of course, all matter we know is unique in that sense.
Even when we ignore that huge fraction of dark energy, we’re still only composed of 15% of the total. (As is, again, all the matter we know.)
Within the tiny fraction of normal matter, of six quarks, three electron types, and three neutrino types, everything we see or touch is composed of only two of the six quarks and one electron.
Let me stress this: Only three particles comprise all atoms: up quarks, down quarks, and electrons. All chemistry is largely based on just the electrons.
Further, we only experience one of the bosons (the photons).
We never experience the W-, W+, or Z0, bosons, nor do we experience the gluons or the Higgs boson. We also never experience the other four quarks, any of the three neutrinos, or the other two electrons. We do experience gravity, but currently it’s not considered a particle (the boson, the graviton, is theoretical and beyond our ability to observe).
Our entire experience of reality is based on four sub-atomic particles: Three Fermions and a Boson. Sounds like a movie title.
This doesn’t make humans special. As I say, it applies to all the matter we experience. But it struck me that normal matter is kinda special from the point of view of the universe.
Ordinary matter is pretty small potatoes to the universe. Its biggest client by far is dark energy — the ripping apart force. Dark matter — the pulling together force — is still big business, but definitely secondary. Dark energy is ultimately all that’s going to matter — the Big Darkness of Entropic Heat Death is the final act.
Compared to commerce like that, we’re a kid’s lemonade stand set up for an afternoon. (Although it may be that we’re the only lemonade stand in the city, if not the country.)
So we’re special in being so very small as well as being unique. That might even make us dear to the universe.
As an aside: Dark energy, as its name implies, seems to be a force of some kind, although we have no idea what it really is. We only know it because of its apparent effects on galaxies.
Dark matter is more of a mystery. We again only know it by its cosmological effects, and there’s currently a big controversy over whether dark matter is a particle, a family of particles, a fluid, or an extension of general relativity. Particularly vexing is failing to find any sign of a particle. As such, dark matter particles are starting to enter supersymmetry territory — windows are closing, candidates are being eliminated, it’s not looking good for WIMPs and MACHOs.
What once seemed a fringe, if not crackpot, theory — modified gravity — is now looking much more viable. The more data we gather, the more the scale seems to tilt in favor of such theories. I find the evidence increasingly compelling.
(Supersymmetry, on the other hand, is a theory that seems well past its expiration date. There has been no sign of supersymmetric particles, and with so many windows closed, remaining theories are pretty baroque.)
Finally, there is that here we are trying to figure out the universe, and that seems kinda special, too. Kinda excellent. Intelligent life seems to invent things mere physical reality doesn’t: justice, information, algorithms, literature, morality, digital watches.
We, and all life, are a major exception to the cruel tyranny of entropy, the unwinder of everything. It’s special that reality provides that simple building blocks, plus time, energy, and some natural rules, generate increasing complexity from biochemistry on up to bloggers. It’s an astonishing progression.
I can’t help but think it’s special — life is a special exception to entropy, we’re made of special stuff, and our brains are arguably pretty special.
Stay special, my friends! Go forth and spread beauty and light.
October 19th, 2021 at 7:23 am
Protons electron neutron is enough Higgs boson graviton supersymmetry string theory adds more complication rather than making the problems simple Spread light and be light You said is correct There is great sloka from Gita “do not lament for unsolved mystery”
October 19th, 2021 at 10:55 am
Well I’m certainly a big fan of mystery in life and in stories! Science doesn’t lament them so much as try to solve them. That view can, I think, go too far, though. Scientism is almost a religious belief — a Yin-only view — that thinks science is everything and all mysteries can be solved — everything can be solved.
But even science tells us this is impossible. I deeply appreciate the world that Gödel, Turing, Cantor, and Heisenberg, have shown us. Math can’t prove all truth; not everything can be computed; some things are uncountable; reality is fuzzy. Scientific limits on what we, or anyone, can know, even in principle. I love living in that world.
The thing we keep finding about simple problems is that they refuse to stay simple. At first light just was, but then we noticed it works like waves. Cool! But then we also noticed it works like particles. And that connected with another mystery about why all ovens don’t become white hot and melt — the simple math we had said they should. Quanta knocked on our door and demanded they be admitted and recognized.
Even math does it to us. I just needed to count my sheep (and jugs of wine and coins and etc). The natural numbers were fine. But then I needed to do 4-7=? and a new kind of number, integers, was needed to do subtraction. And they were fine until I needed to do 7/4=? and I needed another new kind of number, rationals, to do division. Okay, yay, now I can do all the maths,… at least until I look closely at circles or the length of a diagonal across a 1×1 square (i.e. √2), and then to make sense of the world I need yet another new number kind, the reals. The ancient mathematicians throughout the ancient world all recognized these.
More recently that trend continued because of the belief that x²+1=0 must have a solution. (More specifically, that all polynomials have roots.) Solving that requires admitting the complex numbers to the party (which is starting to get crowded, loud, and fun).
Some mysteries are forever beyond us (certainly spiritual ones are), but some mysteries are just hidden until we turn the right corner or look behind the right tree. The universe often hands us the answer when we ask the right question. But, yes, we need also to listen for when the answer is “Mother isn’t telling!” 😉
October 20th, 2021 at 6:20 am
Yes Let us try a time travel👍
October 20th, 2021 at 8:57 am
Yes, I’ve been waiting for my future self to come back and give me the plans for his time machine! 😀
October 23rd, 2021 at 1:06 am
Time dilation and relativity Please brief it Waiting your writing
October 23rd, 2021 at 9:07 am
True, there are ways to jump forward; that’s not prohibited. FWIW, I covered SR in detail some years ago; see this Special Relativity series.
October 23rd, 2021 at 10:55 am
(If you’re particularly interested in time dilation, the two posts that discuss it explicitly are: SR #22: Relative Time and SR #23: Light Clocks.)
October 19th, 2021 at 10:59 am
I forget which scientist said this in which book, but someone I read recently pointed out that, dark energy aside, it’s a little weird to contemplate how the entire galaxy is just 15% of ordinary matter floating inside a much larger bubble of 85% dark matter.
Alternatively, that gravity changes that much on large scales such that it appears 85% of the mass of galaxies is missing.
October 19th, 2021 at 5:19 pm
We might well be special in the sense of being a civilization producing species. Unless interstellar travel is impossible, or so monstrously difficult no one bothers. Or every civilization destroys itself. Or “transcends” in some manner within a few millenia of where we are. Or uploads themselves into virtual paradises and ignores the physical universe. But most likely civilizations are very few and far between.
I haven’t followed the dark matter vs MOND debate closely in a while, but it sounds like the effects are too uneven and lumpy for MOND to be the complete solution, although it might turn out to be part of it. Seems like the disturbing possibility is that dark matter doesn’t interact with familiar matter at all, except through gravity. It also sounds like it doesn’t interact with itself. I sometimes wonder if “dark mass” wouldn’t have been a better name.
October 19th, 2021 at 7:55 pm
Yeah, there’s a compound problem in terms of our knowing about alien civilizations. First the chance that they even exist, then the chance they both choose and are able to be space travelers versus being happy where they are or, as you say, transcending somehow. That’s why I focus on only the first possibility, that they exist in the first place.
Which we’ve talked about plenty, so I won’t repeat. In this case I was amused by the notion that we’re rare in the what we’re made out of sense. It struck me as weird that we, and everything we know, come from a very small fraction of the total, and even a small subset of the everything building blocks.
Neither DM nor MOND account for all the observations, both have gaps, but the latter has been gaining a lot of ground in the past years due to new results. There’s a faint whiff of Ptolemy/Copernicus in how so many have the attitude, “Dark matter exists, of course, we just need to find it.” Other physicists have made similar statements about SUSY and ST, and it’s an unfortunate bias. (Just as bad, obviously, “MOND exists, of course, we just need to prove it..)
For a while I’ve been reading Dr. Stacy McGaugh’s blog, Triton Station. Dr. McGaugh began all in on dark matter, and his research program was investigating its properties. But he found himself overwhelmed by the data, and developed a skeptical agnostic view that now leans strongly MOND. His blog is well-worth reading if you’re interested in the topic. It’s about both the data and the sociology of DM vs MOND.
(As you may already know, MOND is unfortunate short-hand for modified gravity theories. Most of them are trying to modify Einstein, not Newton. And Milgrom’s MOND is just one of those theories.)
October 20th, 2021 at 11:45 am
I’m familiar with the observations that MOND (broadly construed) can’t account for, but less familiar with what DM is missing. Often I see DM skeptics focus on the failure to detect particles, but that detection seems to hinge on DM interacting with regular matter in a detectable fashion. Those failure do seem like they rule out specific version of DM, but seem less damaging to the broader conception.
I do occasionally read McGaugh’s blog (you turned me onto it a while back), but his posts tend to be long and technical, so I usually just skim the early sections. I’ve definitely seen that he feels exasperated with his colleagues, that they aren’t following the evidence, but I haven’t found him clear and succinct in discussing that evidence. (I’m probably not the intended audience for his posts.)
October 20th, 2021 at 1:02 pm
I’m afraid my interest in the DM vs MOND question is too mild for me to answer your question with any detail or authority. All I take away from what I read is a kind of abstract. It’s the sort of thing we talked about on one of your recent posts: weighing credence along various axes and coming away with a judgement. All I can say with any authority is my view has shifted from accepting DM as likely (and MOND as almost crank) to agnostic parity. I think I do have something of a counter-reaction to the sociological issues that causes me to be slightly more sympathetic to MOND than DM. That surprises me because long ago I really did think MOND was crackpot. (Which probably came from a bias favoring Einstein.)
Anyway, huge caveat tendered, my sense is that when all the data are considered, the two theories fit better with some than others. Different some and others in both cases, of course. All the data, as I understand it, includes (but isn’t limited to), galaxy rotation curves (for all galaxies we can measure), gravitational lensing, galaxy velocities relative to other galaxies, galactic clusters, the CMB, globular clusters, dwarf galaxies, and I’m sure more. The problem with this level of astronomy is the observational data we can gather is so limited and in need of interpreting.
If DM is a particle or a fluid that only interacts with gravity, yeah, detection is hard. But if it’s actually matter of some kind, there’s over five times as much of it right here with us right now. Our regular matter is light foam distributed in lumps throughout this smooth much denser matter. I guess that’s actually one thing that’s a factor in my thinking. If DM is true, it’s true right here right now, we’re embedded in that much denser invisible matter. If MOND is true, it’s only true way out there at vast distances.
These days the technical parts of Dr. McGaugh’s blog would be where the meat is. He is, at least in those, writing for the cognoscenti (which isn’t to say I belong to; I’m more the kid brother listening in). There might be something succinct in his earlier posts. Next time I’m moved to comment there, I’ll ask. Or suggest he create one. He doesn’t seem to have pages like some blogs, just posts. It’d be great if he created a summary page.
October 23rd, 2021 at 10:57 am
Just noticed that Edge has changed to a much more readable font on my system. (The change might have happened earlier, but I just noticed it now.) It’s especially apparent in the dropdown menus.
Nice! Their font always looked so wan and weak before.
October 26th, 2021 at 8:07 pm
Drat! I meant to also mention how we’re very near absolute zero when it comes to the range of temperatures present in the universe, and essentially at absolute zero given the possible range of temperatures.
It’s yet another way that we’re kind of unique. Rare in the matter budget, even more rare in the energy budget, made of just three particles, extremely close to the beginning of time, and extremely close to absolute zero.
And we’re self-aware and can invent things like digital watches.
February 6th, 2022 at 1:59 pm
[…] The Fermi Paradox, Simple Probabilities, and Are We Special? for […]
October 11th, 2022 at 9:42 am
A non-exhaustive list of things that might be factors (with 10⁻⁴ odds) in the simplified equation of the odds of intelligent life arising and becoming a galactic player:
My question is whether there are at least five of these with a 1/10000 chance — on average — of happening. (Some might have smaller odds, but others might have greater ones, so what matters is the average odds of five necessary events.)
Because if so, the odds of humanity are (10⁻⁴)⁵=10⁻²⁰ — very small compared to the 2.5×10¹¹ stars in the galaxy. Including the whole Local Group only expands the star count a couple orders of magnitude. Call it 10¹³ or so. We need to consider all the stars in the visible universe, roughly between 10²² and 10²⁴, before the numbers get high enough to make the odds comfortable.
Keeping in mind that (10⁻⁴)⁶=10⁻²⁴, so if there are six events with an average of 10⁻⁴ odds, then the odds are we’re rare even in the entire visible universe.
So much for the Copernican Principle!
January 19th, 2023 at 11:22 am
[…] That’s all there is to this entry, and I’m no longer sure what I meant by it. In fact, I believe the human race is rather unique. (Which is one reason I don’t believe in alien visitors, but would love to see […]